Ptotographing sun / solar eclipse. ND filters. 100mm square filters.

This August I am going to be directly in the path of the solar eclipse. I would like to try my hand at photographing the eclipse. I figure in order to have any chance of capturing any decent images I had better start practicing now.

From what I have read there are 2 distinctly different eclipse shots. The partial eclipse shots where the moon is moving in front of the sun and the total eclipse shots of the sun's corona where the sun itself is completely blocked but the corona of the sun is visible. My understanding is the corona shots are made without any type of filter but the shots leading up to and after the total eclipse are equivalent to photographing the full sun trying to capture sun spots. I figure I can practice before the eclipse by trying to photograph sunspots to gain some valuable experience prior to the actual event.

I am thinking of starting off by purchasing this filter set:

https://www.amazon.com/gp/product/B01N7KBZ7X/ref=ox_sc_act_title_4?ie=UTF8&psc=1&smid=A117K1DEQYNJIS

With an ND-2000 and an ND-64 filter I believe I should have strong enough filters to photograph the sun? What do you guys think? These ice filters say they do filter IR and UV and the ICE filters seem to have a following for their price vs performance.

My plan is to experiment with my old Sony A33 when practicing and if all goes well use both my A33 and A77 plus some film cameras on the day of the eclipse.

I have also been looking at some 100mm square and 100mmx150mm rectangular filter sets. I know I would rather get glass filter over plastic filters but that is about all I know about the square filter world. It looks like these square filters mount via the filter threads on your lenses just like normal filters? Are all the square holders pretty much the same or are some better or more convenient to use than others?

I randomly chose these filter holders:

https://www.amazon.com/gp/product/B01JLNU6WS/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A1K2QC0OJF2HTS

Mainly because of price. Good??? Bad??? Better available for less?

I do not want to spend a ton of money on filters and equipment. I figure I might use some ND filters in the future but not often. I figure the solar specific filters would be one use only filters... then pretty much nothing to do with them but throw them away. I might pickup some of the really cheap reflective mylar solar filters for some of my film cameras if I have some luck with experimenting with the ND filters on my digital A33.

I do have a Sigma 8-16mm lens that will not mount a regular filter because the front of the lens protrudes past the filter rings. On occasion it would be nice to hang a circular polarizer in front of it which would require large square filters and some rigging.