You'll greatly water down the effect of your whole Word Wall by putting words other than those for which it was intended. Use other places in your room for thematically related words, compound words, content words, seasonal words, etc. Also, don't clutter the walls with those other words. Change out the seasonal words when it's no longer that season. Also, let's be sure that we understand the difference between spelling and vocabulary.
Spelling is a writing skill and vocabulary is a reading skill.
It is the mark, however, of a literate person to spell and use high-frequency words correctly. Our principal wants the Self-Selected Reading Block to occur the last 30 minutes of the day so that the children can wind down before getting on the buses. So we don't have time to conference with our students during SSR Block. The conference time during SSR Block is one of the most valuable components of the 4-Blocks Model. First and foremost, you just need to have a few minutes to talk individually with your children throughout the week and to see them as individuals rather than as a class.