stand leveling advice

[CLINT]

Ok so if this is in the wrong place feel free to move it.I am starting the build for my 150g and have built the stand, removed a doorway and and now I'm a little stuck.Seems like everything else in my house. The fellow that built it(my dad)did a lot more cutting than measuring and well, the doorway I want to put my tank in isnt level. There is about a 1/4IN difference front to back.Now the question is how do I go about fixing it without having it come crashing down or look like my kids built it.LOL.I dont think self leveling compound would hold up and I dont want to scab wood on to get it up to height.Would it hurt to take a hand planer and take it down in the front to bring it into level or would the difference in height make it unstable somehow.Probably a dumb question but I figure I cant be the first to have their stand sit funny and since the wife is allowing me to do this I want to make it as painless as possible.Thanks for any input.Clint