Instead of trying to fill the grain with resin or multiple coats of clear, use a paste wood filler. You can get it on line from Rockler; I believe they sell the Behlen's brand. Paste filler is available in many colors, and the stain used is of a much higher quality than Minwax. To apply, you mix the filler in the can, then apply liberally to the wood. I use a plastic bondo spreader to force the filler down into the pores of the wood by working it back and forth across the grain. Usually, I let it dry for about 10 minutes, until it looks hazy; then I wipe it off, wiping across the grain of the wood so as to not pull it out of the pores. I let it dry overnight, then wipe again, this time with the grain, to remove any excess. To be safe, I wait another 24 hours, then start spraying the clear. It still requires a couple of extra coats of clear to finish filling the grain, but not many-maybe 2. I spray 3 coats, hard block sand to 800, then spray 3 more coats. Once that is hard blocked to 1000, I can tell if I need to shot any more clear before final cut and buff; usualyy, I will shoot 2 more coats, just to be sure I've got enough film build for final cut and buff.
No pictures, but I have been finishing furniture for 40 years, and car stuff for the last 3. I am constantly experimenting with different finishes and finishing techniques. In fact, that's how I found SPI; I was looking for a durable clear for tabletops, as my supplier, ML Campbell, stopped making a modified acrylic lacquer. The modified acrylic was more durable than nitrocellulose yet still had the warmth, clarity, and buffability of nitro, while all of the pre- and post- catalyzed lacquer products are too plastic looking and get milky when rubbed. The SPI clear has everything I need, so I have switched to it.